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Conjunctival provocation tests with codeine phosphate. Effect of disodium cromoglycate
A M Campbell1, P Demoly, F B Michel
1Clinique des Maladies Respiratoires, Montpellier, France.
Annals of Allergy
|July 1, 1993
Summary
Ocular mast cell activation by codeine phosphate was demonstrated in humans, with significant histamine and PGD2 release. Disodium cromoglycate effectively blocked these mast cell responses in the eye.
Area of Science:
- Ophthalmology
- Immunology
- Pharmacology
Background:
- Ocular mast cell reactivity is not well understood in humans.
- Codeine phosphate is known to activate connective tissue mast cells.
Purpose of the Study:
- To investigate the reactivity of ocular mast cells in humans.
- To determine if codeine phosphate can activate ocular mast cells and trigger mediator release.
- To assess the effect of disodium cromoglycate on codeine phosphate-induced mast cell activation.
Main Methods:
- Ten healthy subjects underwent ocular provocation tests with increasing concentrations of codeine phosphate.
- Schirmer strips were used to collect samples from under the eyelid for five minutes.
- Histamine and prostaglandin D2 (PGD2) levels were measured following codeine phosphate challenge.
- A negative control was performed, and the effect of disodium cromoglycate was evaluated.
Main Results:
- All subjects showed a positive reaction to 10(-1) mg/mL codeine phosphate.
- Histamine release increased significantly (P < .018) from 7.06 +/- 4.19 nM/L to 18.2 +/- 15.7 nM/L.
- PGD2 release was observed (0 ng/L in control vs. 273.3 +/- 408.9 ng/L with codeine phosphate).
- Disodium cromoglycate successfully inhibited the release of both histamine and PGD2.
Conclusions:
- Codeine phosphate is a potent activator of ocular mast cells in humans.
- The release of histamine and PGD2 indicates mast cell degranulation.
- Disodium cromoglycate demonstrates efficacy in blocking codeine phosphate-induced mast cell activation in the eye.